Telephone system.



PATEN'I'ED JAN. 27, 1903.

W. HUHNE. TELEPHONE SYSTEM.

APPLICATION FILED APR 17, 1902 110 MODEL lUNlTED STATES PATENT (lemon.

WiLHELM I-IOHNE, OF scHoNEnERc, GERMANY.

TELEPHONE SYSTEM.

SPECIFTGATION forming part of Letters latentNo. 719,219, dated January 27, 1903.

Application filed April 17, 1902. Serial No. 103,285. (No model.)

T0 coll 'LU7bO7IL it may concern;

Beit known that LWILHELM HGHNE, a citizen of the Empire of Germany, residing at Schdneberg, near Berlin, Germany, have invented certain new and useful Improvements in Telephone Systems, of which the following is a specification.

The object of this invention is to provide means whereby the joining up in parallel of two stations on the line, due to the presence of a switch-plug in a socket when the same should have been previously removed therefrom, is avoided. For this purpose the invention consists of a telephone system comprising a line-wire for each station, a call-bell at each station, a line-wire for said call-bells, a common return-wire for the station linewires and call-bellline-wire,abatterybetween the call-bell line-wire and the common returnwire, conductors connecting said call-bells with said line-wires and common return-wire, a switch-box at each station provided with sockets connected each with the station linewires, a plug for each switch-box, a signaling switch connected with said plug, a conductor connecting the call-bell with said switch, a local circuit at each station having the usual microphone-battery and primary coil, a receiver at each station in series with the station line-wire and common return-wire, a switch at each station adapted for cutting in the local circuit and cutting out the call-bell, and a third switch connected with but insulated from said local-circuit switch, said third switch, switch-plug, signaling-switch, and call-bell being connected all in series with each other and the whole in parallel between the station line-wire and the common returnwire and said third switch being springactuated normally into open position, so as to prevent the station at which it is located being connected in parallel with either communicating station when the switch-plug of said station remains in a socket of the switch-box corresponding to one of said communicating stations.

The accompanying drawing represents a diagram of a telephone system having three stations and laid out according to my invention.

A, B, and 0 indicate the stations.

, e e e are the switch-boxes, provided each with a switch-plug, respectively, d (1 d a b c are the line-wires for the respective stations.

7; is the call-bell line-wire, and sis the common return'wire.

w is a battery connected with the call-bell line-wire and the common return-wire.

g g g are the local batteries.

h h 77,2 are the respective telephone-receivers.

it" i are the microphones in the respective local circuits.

t i t are Morse keys contacting, on the one hand, normally with contacts m m m and capable of being depressed into contact with contacts Z Z Z for signaling-i. 6., calling a station with which it is desired to speak. These keys may be termed signaling-keys.

V W indicate the call-bells, mounted upon the boards 1' "1" r respectively.

n v o indicate the conductors attached to or connected with the plugs cl d 01 respectively. These wires are not connected directly with the respective main-line wires a Z) a, but said wires o 'v' o connect, respectively, with springs s s The opposing contacts y y g are connected with the signaling-keys, respectively, If '6 2?. Each station is provided with a switch for cutting out the bell and cutting in the local circuit, said switches being composed of springs 11. n 71 respectively, adapted when depressed to break connection with contacts (1 q (1 connected with the bell, and make connection with contacts 0 0 0 connected with the receivers h h h", respectively, and with contacts 19 13' 19 connected, respectively, with the microphones t t" 1' ff f are the induction-coils, the primary of which is connected in the usual manner in the local circuit and the secondary in series with the telephone-receiver.

When station A desires to speak with station 0, plug (1 is inserted in socket C of switchbox e, key 25 is depressed into connection with contact Z, and simultaneously switch n is depressed-i. e., moved in'the direction indicated by the arrow. By this movement the third switch 8 is also actuated and brought into connection with contact 1 The two switches n and s are connected by a connecting-piece u of anysuitable insulating material,

so that when n is actuated switch 8 is also moved. Similar insulating connecting-pieces u a connect the switches n with s and n with 3 respectively.

made between tand land 8 and y, as described, the circuit is as follows: battery w, call-bell line-wire 7t, terminal K at A, switch 25, contact y, switch 8, terminal St, wire 1;, plug d, socket IO C, station line-wire a, terminal L at station 0, switch 25, contact m terminal W, bell W terminal W, contact (1 switch n terminal ZE, and common return-wire z to battery 00. Station A having called 0 and obtained reply, signaling-switch t is released and conversation carried on between A and 0, switch it and also 3 being retained in de pressed condition during conversation. A and 0 having finished, switches 01 and s are released, the former moving back into contact with q. Assuming, however, that the switchplug d is not withdrawn, as it should be, from socket C, but remains therein, due to carelessness or any other cause, and now station O desires to speak with station B, station 0 inserts plug d in socket B depresses key if and switchn switch 3 being thereby also depressed, the bell at station B is thereby rung, but owing to the switch 5 at station A the bell at said station is not rung, whereas were said switch not provided but the plugwire directly connected to terminal L at station A the bell at station A would be actuated, owing to the plug being located still in its socket C, thereby connecting the bell in parallel with the bell of station B on the line. The wires 2) o 1: of the plugs d d d are not connected directly with the line-wires, but are connected with these switches s s .9

result of cutting out the bell automatically when releasing the switch it, notwithstanding that the plug remains in its socket. This will be clear upon following out the circuits, which are as follows, when C depressed key 23 and switch 01?: Signaling-circuit O to B, from battery X successively through 75, K at O, Z 25*, 3 .9 S15, 0 d B 19, L at station B, t, m, W" at station B, bell W, W, q, n, ZE, z, w. Were wire U connected with L of station A current would also flow from Z at 0 through 75 L at 0, ct, C, d, o, L, if, m, W, WV, N, g, n, ZE, 2, as, k, K at O, Z thereby ringing bell W at station A. Switch 8, however, being interposed in wire '0 and being in open condition, opens the circuit stated and no current can flow over the same, and the bell WV is thereby not actuated. Station B upon hearing bell W depresses switch it, 8' being also thereby depressed, and takes receiver h. By depressing n the signalingcircuit described is broken between n and q and bell W ceases ringing. 0 having already. placed receiver 77/ at his ear, when B speaks C releases key t The speaking-circuits are as follows, the

Connection being now respectively, thereby attaining the desired i secondary having been completed when B depressed switch 'n: local at O; 9 KM, primary of f M, 11 19 m ZE, g local at B, 9, KM, primary of f", M, '11, p, n, ZE, g; secondary between C and B; secondary coil of f, W, m 15 M, St, 0 d B 1), L at B, 25, m, W, secondary of f, T, h, 0, n, ZE, z, ZE at 0, W 0 h", T, secondary off Were wire 1; at A connected directly with L and plug d in socket 0 current would also flow from 26 through L at C, a, C, d, 2;, L, t, m, W, W, W, q, 'n, ZE, z, ZE at 0, M, 0 71 T, secondary of f W, m t thereby connecting station A in parallel with B, part of the current in such case going through telephone-receiver h and part through bell W, thereby splitting the circuit and rendering conversation indistinct, if not impossible, between 0 and B. This disadvantage is entirely avoided by the switch 8, as the same being in open condition no'current can flow over the circuit indicated to A, but the same is confined to B and 0.

Having thus described my invention, I claim as new and desire to secure by Letters Patent- In a telephone system, the combination of a line-wire for each station, a call-bell at each station, a line-wire for said call-bells, a common return-wire for the station line-wires and bell line-wires, a battery between the bell line-wire and common return-Wire, conductors connecting said bells with said linewires and common return-wire, a switch-box at each station provided with sockets connected each with the station line-wires, a plug for each switch-box, a signaling-switch connected with said plug, a conductor connecting the bell with said switch, a local circuit in each station, having the usual microphone, battery and primary coil, a receiver at each station in series with the station line-wire and common return-wire, a switch adapted for cutting in the local circuit and cutting out the bell, and a third switch connected with but insulated from said local-circuit switch, said third switch, switch-plug, signaling-switch and bell being connected all in series with each other, and the whole in parallel between the station line-wire and the common return-wire, and said third switch being spring-actuated normally into open position, so as. to prevent the station at which it is located being connected in parallel with other communicating stations notwithstanding the switch-plug of said station remains in connection with a socket of said switchbox, substantially as set forth.

In testimony that I claim the foregoing as my invention I have signed my name in presence of two subscribing witnesses.

WILHELM HOHNE.

Witnesses:

HENRY HASPER,

WOLDEMAR HAUPT. 

